Optical fiber connectors are an essential part of substantially all optical fiber communication systems. For instance, such connectors are used to join segments of fiber into longer lengths, to connect fiber to active devices such as radiation sources, detectors and repeaters, and to connect fiber to passive devices such as switches and attenuators. The principal function of an optical fiber connector is to hold a fiber end such that the core of the fiber is axially aligned with the optical path of the component to which the connector is mating (e.g., another fiber, a waveguide, an opto-electric device). This way, all of the light from the fiber is optically coupled to the other component. It is well known that to effect optical coupling and minimize Fresnel loss, there must be sufficient “physical contact” between the optical path medium, which, in the case of optical connectors, is generally fiber.
Recently, to accommodate the ever-increasing number of fiber interconnections, MT ferrules have been introduced which accommodate an array of fibers. An example of a well-established MT connector is the Lightray MPX® optical interconnect system (Tyco Electronics Corportaion) which is cable of handling 24+ fibers. To accommodate all the fibers, the mating surface of an MT ferule tends to be larger than those used in single fiber ferrules. As used herein, the term “mating surface” refers to the portion of the ferrule that comes in contact with another optical component, such as another ferrule or waveguide, when the connector containing the ferrule is mated to the other optical component.
Although effective in handling a larger numer of fibers, MT ferrules have traditionally suffered from problems establishing good physical contact among all the fibers. The applicants have identified several causes for the difficulties in establishing physical contact with an MT ferrule, all of which involve the larger mating surface of the MT ferrule. One of the more significant difficulties arises with angular misalignment between the mating surface and the optical component to which the ferrule is intended to mate. Such angular misalignment will be more pronounced with a larger mating surface. More specifically, since angular misalignment between the mating surface and the optical component will cause the edge of the mating surface to contact the component first, a gap will result between the center of the mating surface and the component. Since the fiber ends are typically in the center of the mating surface, angular misalignment will necessarily separate the fibers' ends from the optical component and make physical contact more difficult.
Another reason why physical contact is more difficult in MT ferrules is the fact that a large mating surface is more difficult to deform to achieve physical contact. More specifically, making physical contact is often a function of deforming the ferrule such that the fiber end faces make physical contact. As a surface becomes larger, it becomes more difficult to deform. A greater surface area requires more force to maintain the same pressure. Often the required force is beyond the ability of the connector or interconnection system to deliver.
Yet another problem with establishing physical contact with a larger mating surface is the greater probability of encountering irregularities on the mating surface. The irregularities may be in the form of debris or surface anomalies. Such irregularities may prevent intimate contact with the other optical component and, thus, diminish the physical contact between the mating fiber ends.
Thus, there is a need to improve the physical contact made by a large number of fibers in a single ferrule. The present invention fulfills this need among others.